Such medical tracking references are used to determine the spatial position of objects by means of a medical tracking system which is assigned to a medical navigation system, wherein the tracking reference is fastened to such an object. An adjustable tracking reference comprising a joint, wherein a medical tracking reference comprises a fastening arm and a reference array holding arm to which a reference array is or can be attached and comprises a joint between the arms which can be fixed using a fixing array, is known from EP 1 563 799 A1. The tracking reference comprises a fastening arm via which it is fastened to the object, and a reference array holding arm to which the reference array is or can be attached, which in turn can be localized by the tracking system. A joint is situated between these two arms and serves to enable the reference array to also be arranged differently for different applications or different operating theatre setups, such that it can be detected by the tracking system in any event.
In accordance with the prior art, the joints are for example fitted with fixing screws, i.e. they can be made movable before the reference array holding arm is correctly aligned. However, the joints then have to be fixed again and remain fixed (using the setting screw), in order for navigation and tracking to be able to function.
However, it often occurs that the surgeons performing the treatment do not tighten or do not correctly tighten these fixing screws or setting screws, and that the joint therefore becomes loose again and the reference array moves during the treatment. This completely invalidates the registration, and navigation would lead to incorrect results.